Remote Diagnosis Of 'clunk'

[Schmooth]

Nasty intermittent sound that I can't reliably replicate for mechanics, and they can't find it (it's under warranty). BA MkI auto turbo.

Most often rears its head when reversing to the left (coming out of the driveway).

It's a mechanical noise from the rear (diff?) of the car that is associated with wheel rotation speed. The only way I can describe it is to liken it to a solid wheel with a flat spot rolling on a hard surface. You can feel the vibration through the car as the 'flat spot' or 'slippage' (whatever the hell it is) and can feel the car shift slightly as it happens.

It sometimes occurs when in forward gear if moving slowly and turning a corner (the turning part is what made me think of the diff).

The problem has been steadily getting more pronounced all year.

I haven't got a clue if it is diff/axle/suspension bushes/diff carrier etc.

Any ideas that I can throw at the Ford mechanics?

[Robit28]

I'm not sure but I hear you!

I have exactly the same issue. Car is going in next week for a service and Ford WILL be fixing it (I always get my way).

I will let you know what they come up with but I believe it's a diff problem by the sounds of it.

Rob.

[simonhoare]

probably lsd engaging, get them to change oil and see if it changes. easy first step!

or its about pop

[Schmooth]

Thanks guys.

And Rob, yeah, would love to hear what the end story is.... particularly as I'm about to run out of warranty.....

I like Simon's approach (and would try it in a car without warranty) but would be concerned that it would only be enough to get me over the warranty threshhold and then let go!

[JB]

Good luck guys, this issue has been around since the inception of the BA and then models before.

Do a search plenty of discussion on it.

It's Called driveline shunt or backlash. I describe it as a slackness in the driveline, ford are well of it, but getting it fixed I suggest you get a lottery ticket as you will have a better chance.

Aside form the diff whine, Ihhad 2 gearboxes and 5 diffs and no resolution, the only way to fix it is learn to drive around it, or buy a european car.

BTW it is more apparent in the manual than the auto's.

Cheers

JB.

[iTec]

Get them to re-torque the rear suspension you may have a loose bolt by the sounds of it.

I now get mine retorqued every six months as supposedly its not uncommon for them to find a bolt loose when they do it.

[Schmooth]

It's Called driveline shunt or backlash. I describe it as a slackness in the driveline, ford are well of it, but getting it fixed I suggest you get a lottery ticket as you will have a better chance.

Yeah, it's a shunt as well. That's been getting steadily worse over the last 11 months.... engaging Drive or coming off a closed throttle when coasting is when it is worst... but the 'clunk....clunk...clunk...' when reversing around a corner is what is really concerning me.

[WBT56]

.....Aside form the diff whine, I had 2 gearboxes and 5 diffs and no resolution....

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I cannot believe dealers are still doing this. Basic scientific principles should show that repeatedly replacing an item with no fix to the problem means the problem is not with the item being replaced. We have a G220 on the hoist at the moment with these problems. It has been to four dealers to no avail, and took all of 2 seconds to diagnose and 2 minutes to prove. Fault is in half shaft CV joints, as is the case in most BA's. Ben.

[Schmooth]

Ben,

Are you saying that the half CV joints are what is causing the noise in the back of my car when reversing around the corner? (and sometimes while driving forwards around the coner!)

Or simply for the driveline shunt (or are they one and the same)?

If so, how do you diagnose? (I want to get this sorted once and for all).

[WBT56]

Ben, Are you saying that the half CV joints are what is causing the noise in the back of my car when reversing around the corner? (and sometimes while driving forwards around the coner!)...Or simply for the driveline shunt (or are they one and the same)?...

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They are generally the cause of the power on/ power off clunk, them and the pre-dampened clutch plate in the manuals. A ratcheting noise at low speeds while turning can also be generated by wear in this area. It is a matter of getting a car up on a hoist and checking for backlash. Most people rock the tailshaft and say the total movement generated is in the diff, but you have to watch for movement in the half shaft CV joints, particularly the inners, especially the left hand one. Ben.